The effects of chlorfenapyr on the life history traits and population parameters of Neoseiulus longispinosus Evans (Mesostigmata: Phytoseiidae)

This study evaluated the effects of chlorfenapyr on the life history traits and population parameters of the predatory mite Neoseiulus longispinosus Evans (Mesostigmata: Phytoseiidae). The females of the predator were treated with chlorfenapyr applied at the LC<sub>10</sub>, LC<sub>20</sub> and LC<sub>30</sub> concentrations, which was previously estimated for the females of its prey, Tetranychus urticae Koch (Acari: Tetranychidae), and the effects were evaluated in the F<sub>1</sub> generation of the predator under laboratory conditions. The results revealed significant prolongation of the egg, larval, protonymph and deutonymph periods in the LC<sub>30</sub> and LC<sub>20</sub> treatment groups compared with those in the control. On the other hand, a concentration-dependent decrease in adult longevity was recorded in the LC<sub>30</sub> and LC<sub>20</sub> treatments. The oviposition period significantly decreased from 12.68 ± 0.02 days in the control to 7.04 ± 0.02 days in the LC<sub>30</sub> treatment. The lowest fecundity was recorded in the LC<sub>30</sub> treatment (19.00 ± 0.95 offspring/female), and the highest fecundity was recorded in the control (34.37 ± 0.75 offspring/female). Population parameters also decreased, with the GRR decreasing from 27.61 ± 2.23 in the control to 12.92 ± 1.65 in the LC<sub>30</sub> treatment. Similarly, the intrinsic rate of increase (r) and finite rate of increase (λ) also decreased in the LC<sub>30</sub> treatment (0.190 ± 0.0127 and 1.117 ± 0.0128<sup> </sup>day<sup>-1</sup>, respectively). However, a significantly shorter generation time was recorded in the LC<sub>20</sub> (12.68 ± 0.24 days) and LC<sub>30</sub> (12.21 ± 0.24 days). Survival curves revealed that the shortest lifespan was associated with the LC<sub>30</sub> treatment (23 days), and reproductive peaks were reached earlier under sublethal concentrations. Overall, the results showed negative impact of chlorfenapyr on the biological parameters of N. longispinosus, which may affect its role as a biological control agent.